Electric Leisure Boat Designs

Discussion in 'Boat Design' started by slboatdesing, Aug 7, 2022.

  1. slboatdesing
    Joined: Aug 2022
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    Location: Maldives

    slboatdesing Senior Member

    Hi

    I am new to this forum, this is my first post.

    Great forum, there are things here I cannot imagine.

    As for myself, my family and I are temporarily residing in the Maldives, and just the other day we had a chance to go on some water rides. The towed - water couch, and riding tandem on jet ski. Yesterday I rented what is called an ocean going kayak, costing about $10 per hour as opposed to the Jet Ski which I will need to be trained to ride. It was stable, easy to handle, but paddling was a bit of a chore, with two on board.

    I have driven rented motorboats - having driven one briefly in Florida USA many years ago, and also in Bentota, Sri Lanka. The control of the motorboat through the steering wheel is as precise as controlling a car, I do not know how that was achieved. I prefer motorboats to jets skis any day. I want a steering wheel of some sort.

    I got to thinking how it would be possible to add electric power to the kayak or come up with a low cost electric powered leisure boat with a steering wheel. This is then a purely design exercise, and maybe one day I will be able to build one - cost is not insurmountable even at this stage, however there are other considerations here. It is such a pity that the local water sports place does not see it as economical to offer anything else. If I could speak to the owners and partly fund an import of an electric boat, or even a conversion that would be great.

    The place I visited is visible on Google Earth -Hulhumale, Maldives. See the link to some pictures in this article - the kayak pictured is next to the catamaran in the 4th picture.



    Questions welcome.
     

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  2. slboatdesing
    Joined: Aug 2022
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    Location: Maldives

    slboatdesing Senior Member

    Preliminary design in 3D. The battery is in green, motor placement will have to be underneath. The cost of the boat runs in the hundreds, so maybe an inflatable boat is a better starting point. The modifications will only add to the cost.
     

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  3. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    Welcome to the Forum SLBoat.

    Your kayak proposal above looks interesting, but no doubt complicated and expensive.

    Have you thought about simply putting an electric O/B motor (like a Torqueedo or similar) on to a boat that rows well?
    Lots of interesting plans for a wide variety of boats on Duckworks -
    Plans & Kits - Plans by type - Rowboats - Page 1 - Duckworks Boat Builders Supply https://duckworks.com/plans/rowboats/

    And some more here
    Canoes, Kayaks, and Dinghies - Boat Builder Central https://www.boatbuildercentral.com/product-category/boat-plans/canoes-kayaks-and-dinghies/

    And here
    Motor Canoes https://www.selway-fisher.com/Mcanoe.htm
     
  4. rnlock
    Joined: Aug 2016
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    Location: Massachusetts

    rnlock Senior Member

    How far and how fast does this boat have to go? If it only has to go as fast as that kayak, a trolling motor on a canoe would do the trick. I've seen lots of guys fishing in canoes with a piece of wood stuck on the outside and a trolling motor clamped on. And they usually only use a single battery that might weigh 50 lbs. These days, if the budget allowed it, a lithium iron phosphate battery could weigh less and last longer.

    You could put a trolling motor, since it's light, on the back of a real rowing boat. The battery would have to be closer to the middle, though. You'd want a tiller extension, or you could set up some kind of steering wheel with cables and pulleys. Since you're only there temporarily, I suggest something simple, like the rowing version of Jim Michalak's QT Skiff.
    QT Skiff Plans PDF https://duckworks.com/qt-skiff-plans/
    If anything goes wrong or you run down the battery, you can row back. You may find, like me, that rowing is easier than paddling. Except for the part where you have to turn around to see where you're going, but if someone else is in the boat, they can tell you which way to go. Just be sure to put in some kind of flotation if you build something like this. If you built something like the Roar 2, the battery would last longer, the rowing would be a little easier, and you could go out when the water was a bit rougher. But I think the Roar 2 would take longer to build, and require some extra epoxy and fiberglass.
    Roar2 Plans PDF https://duckworks.com/roar2-plans/
    If you needed to go a bit faster, and got some kind of electric outboard with more power, the power version of the QT skiff might work. If your propulsion has one or two or more horsepower, a pure rowing boat or a canoe generally won't behave properly. I was once in a heavy, 18 foot canoe with 3 other people, powered by a 3.5 horsepower motor. It felt like this (turn the sound off):


    Lots of other boat designers have suitable choices, of course.
     
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  5. slboatdesing
    Joined: Aug 2022
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    Location: Maldives

    slboatdesing Senior Member

    The kayak itself costs about $ 800 new, but compared to a jetski, it is much less. Jet skis are at least $ 8000 used.
    Before I abandon this design, let me post a link to the solar panel powered kayak that was mentioned in these forums. The motors were in the sponsoons whatever those are.

    2 person Small Solar powered catamaran. Pedal board. Wood canoe https://www.boatdesign.net/threads/2-person-small-solar-powered-catamaran-pedal-board-wood-canoe.66715/#post-925785

    The solar catamaran is very close to the ideal design for me - needs to have seats mounted lower down and a steering wheel.

    I am not planning on building anything here, thanks for the links. I want to persuade the owner to buy some more interesting boats or modify existing ones which I can then rent at will, and he could probably make some more profit off these things. A nice two-seater low powered electric motorboat or catamaran would be very attractive.

    I am sure many are experienced in the realities of running an enterprise, so how does that sound as a business plan?
    The Maldives has picked up in tourism, but beaches used to me much more crowded before the pandemic.

    Where - for now this 200 metre or so stretch of beach protected by a reef - in Hulhumale Maldives (screenshot from Google Maps)
     

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  6. slboatdesing
    Joined: Aug 2022
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    Location: Maldives

    slboatdesing Senior Member

    Trolling motors are somewhat expensive, however the solar kayak I just posted is better since I will be boating with coral underneath in shallow water and an outboard will snag things as well as being a problem when beaching. A prop tucked away under the boat in some sort of protective enclosure would do the trick.

    The QT Skiff is a nice classic boat but as I said outboards won't work here.

    The Roar 2 is a beautiful classic little boat, it will be on my wish list for boating experiences some day.

    I really like the jet kayak - I only need to go about 6 knots or so, at least to progress against the wind at worst I could paddle back. An electric ducted fan would work, I need to or a large fanboat type propulsion system - these come with their own safety issues though.

    Some more designs. Let's see if I can find a ducted fan that will put out..how much does this need... say 55lb thrust typical of trolling motors? Seems too much to ask.
     

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  7. slboatdesing
    Joined: Aug 2022
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    Location: Maldives

    slboatdesing Senior Member

    Just came across this. How do you protect the motor when going ashore? Will need some sort of protective cage I think.

    First flexible water sports jet-engine | WordlessTech https://wordlesstech.com/first-flexible-water-sports-jet-engine/

    Or it could be a fan-kayak. These things need a lot of power I think, not sure how winds will affect this.

    Since the last post I have come across some nice designs that actually work, and are very close to what I would want.

    Non- Electric:

    Jet-Powered Kayak From HydraRide | The PowerKayak PLUS http://www.hydraride.com/jet-propelled-watercrafts/powerkayak-plus-jet-powered-kayak/

    (An electric conversion would be nice)

    Honda GX31 Airboat - Sevylor Dive Yak
    (Engineering seems quite solid here)

    The Dive Yak looks to be a very robust design. Funny name for a boat. $ 500 used?

    Electric:



    8 Best Motorized Kayaks for 2022 – Buying Guide and Reviews | Boat Safe | Water Sports, Product Reviews, and Nautical News https://www.boatsafe.com/best-motorized-kayak/



    Would like anyone to comment on safety issues - a leisure boat with fast propeller out in the open might have its risks. What happens when it overturns?
     

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    Last edited: Aug 8, 2022
  8. clmanges
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    clmanges Senior Member

    You get to swim home. Then you may get to pay someone to retrieve it.
     
  9. rnlock
    Joined: Aug 2016
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    rnlock Senior Member

    When it overturns, while running, something breaks, unless it wasn't running because someone with sensitive ears had already broken it.

    A jet drive will probably be fairly inefficient and limit range when battery powered.

    A trolling motor will use less draft than your original electric kayak proposal, and can be protected by a skeg. I'd be surprised if they don't pivot up when hitting things. A saltwater trolling motor and a deep discharge battery will probably cost less than the kayak mentioned above. I suppose, if you didn't mind being embarrassed, you could hook up an electric motor to some sort of paddlewheel. There are, in fact, commercially available, pedal powered paddlewheel boats which could be adapted. However, they're really easy to pedal if you don't mind going slowly. You'll find a whole bunch of examples if you do an internet search on "pedal powered paddlewheel boat".

    You might find these interesting, but they cost a large fraction of the cost of a Jetski, probably because they're made in much lower quantities. They use a propeller, which makes them more efficient, but less vulnerable.
    Pedal (Paddle) & Electric Boats by Nauticraft https://www.nauticraft.com/

    I once rented a little two seat catamaran with what looked like two outboard motor lower units, with pedals. One or both could be put in the water, and it was easy to go reasonably fast. Even easier to go slowly.

    The solar powered boat would need battery backup, or else it would lose power every time a cloud went over, or when it was heading south. However, it might be enough to keep a battery topped off if it wasn't used too many hours per day.

    All of this is so much more trouble and expense than using oars. It's easier to row at a walking speed than to walk. Oars are cheap, simple, obvious, practical.... Phil Bolger, referring to motorboats, wrote: "... the way some people use them is like trying to do your shopping by airplane.."
     
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  10. slboatdesing
    Joined: Aug 2022
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    Location: Maldives

    slboatdesing Senior Member

    I think the non-electric boats generate too much of noise to be useful. If I knew about paddling I would have rented one long ago instead of going for the motorboat rental. Turns out there is a decent kayaking thing from where I was.

    Is this tutorial on paddling any good?



    Let me know where I can find more info. I will 'oar' it to you.

    How do you handle this overturning thing? In small planes you have really no options, but in boats - do you plan for ending up in the water and being rescued or is that an outside option?

    So we are all in agreement that I should give up my electric dreams and go kayaking this Saturday. That's it then.
     
  11. IronPrice
    Joined: Jul 2017
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    Location: NZ

    IronPrice Senior Member

    There are already kayaks available with drop in batteries and bolt on jet units as suggested above. They all tend to protrude a little below the hull, so that they can get good flow of water. That steering wheel will cause you to lean forward which will bury the nose of the kayak.
     
  12. clmanges
    Joined: Jul 2008
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    Location: Ohio

    clmanges Senior Member


  13. slboatdesing
    Joined: Aug 2022
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    Location: Maldives

    slboatdesing Senior Member

    Like this?





    I know. 5 mph though.

    see the comments.

    "Super complicated, over priced, inefficient and obnoxiously loud. Those are just a few reasons why this may not be the best idea."
     
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